Composite panes with solar shielding coatings

Abstract

A composite pane (100) comprising an outer pane (1) having an outer side surface (I) and an inner side surface (II), an inner pane (2) having an outer side surface (III) and an inner side surface (IV), and a thermoplastic intermediate layer (3), wherein , , , the thermoplastic intermediate layer (3) bonds the inner side surface (II) of the outer pane (1) to the outer side surface (III) of the inner pane (2), the composite pane (100) has at least one solar radiation shielding coating (4) between the outer pane (1) and the inner pane (2), the solar radiation shielding coating (4) has the following layer arrangement starting from the inner pane (2) and facing the outer pane (1): - a first dielectric module (M1), - a first silver layer (Ag1), - a second dielectric module (M2), - a second silver layer (Ag2), - a third dielectric module (M3), - a third silver layer (Ag3), [[ID=​​​​​​​

Description

[Technical field]

[0001] The present invention relates to a composite pane having an improved solar shielding coating and uses thereof. [Background technology]

[0002] Composite panes with conductive coatings are well known in the vehicle sector, for example as windshields with a heatable transparent coating. The coatings typically comprise several silver layers applied alternating with dielectric layers to ensure, on the one hand, high electrical conductivity and, on the other hand, sufficient transmittance in the visible spectral range. More complex conductive coatings for windshields are also known. They can be used, for example, as IR-reflecting coatings to improve thermal comfort by reducing heating inside the vehicle. However, the coatings can also be used as heatable coatings, by connecting them to a voltage source so that a current flows through the coating. Suitable coatings include conductive metal layers, in particular based on silver. As these layers are prone to corrosion, they are usually applied to the surface of the outer or inner pane facing the intermediate layer, without contact with the atmosphere. Silver-containing transparent coatings are known, for example, from WO 03 / 024155, US 2007 / 0082219, US 2007 / 0020465, WO 2013 / 104438 or WO 2013 / 104439.

[0003] In particular, in the automotive sector, solar shading coatings are required that are not only heatable but also have a low total solar transmittance (TTS), low external reflection, and a neutral or blue reflection color. In particular, yellow, red, and purple reflection colors are considered to be intrusive and should be avoided. Good solar shading properties of vehicle glazings are also desirable from an environmental point of view, since they also contribute to reducing the energy consumption of the air conditioning system. In electric cars, reducing the energy consumption of secondary systems such as air conditioning and heating means an increased driving range. In electric vehicles, DC / DC converters are commonly used to increase the on-board voltage from 14V to a supply voltage of 42V, thereby operating a heatable windshield. Heatable solar shading coatings designed for vehicles with internal combustion engines are generally designed for a supply voltage of 14V and are not compatible with the operating range of 14V / 42V DC / DC converters. In this respect, it is not advisable to simply increase the layer thickness of known heatable solar shading coatings designed for a 14V supply voltage in order to obtain a reduced total solar transmittance (TTS). A low total solar transmittance (TTS) is generally associated with a high external reflectance of the coating. In practice, however, the lowest possible values ​​of both are desirable. Furthermore, the windshield must comply with the legal specifications according to the process for testing the light transmission of motor vehicle windows laid down in ECE-R 43, Annex 3, §9.1, which results in a reduction in the total solar transmittance TTS. L must be at least 70%, which makes it more difficult to achieve a lower total solar transmittance. High demands are made on the optical and electrical properties of solar shading coatings if they are to be used in the automotive sector as heatable coatings, have a visually attractive reflective color and at the same time be compatible with the DC / DC converters commonly used in electric vehicles.

[0004] WO 2019 / 206493 discloses a composite pane for a head-up display, at least one conductive coating on one of the surfaces of the outer or inner pane of the composite pane facing the thermoplastic intermediate layer, and an anti-reflective coating on the surface of the inner pane facing away from the thermoplastic intermediate layer. The conductive coating comprises at least four conductive silver layers with a total thickness of at least 60 nm, in each case a dielectric layer is disposed between the silver layers. Looking from the inner pane towards the outer pane, the third silver layer following the inner pane is the thickest silver layer.

[0005] WO 2020 / 094422 relates to a projection assembly for a head-up display (HUD), comprising at least a composite pane with a HUD area, a conductive coating on the surface of the outer or inner pane facing the thermoplastic intermediate layer, and a projector. The conductive coating comprises at least four conductive layers, in each case arranged between two dielectric layers. The sum of the thicknesses of all conductive layers is at most 30 nm, and at least one of the conductive layers is at most 5 nm thick.

[0006] WO 2020 / 094423 describes a projection device for a head-up display (HUD), which includes a composite pane having a conductive coating and a projector, where the conductive coating includes at least three conductive layers, where the sum of the thicknesses of all the conductive layers is at most 30 nm, and where the conductive layers have a thickness of 5 nm to 10 nm. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a further improved composite pane with solar shading function, where the electrical, energy and optical properties of the composite pane should be further improved.

[0008] This problem is solved by the composite pane according to the invention as claimed in independent claim 1. Advantageous embodiments of the invention are apparent from the dependent claims.

DETAILED DESCRIPTION OF THE INVENTION

[0009] The composite pane according to the invention comprises an outer pane having an outer side surface (first surface) and an inner side surface (second surface), an inner pane having an outer side surface (third surface) and an inner side surface (fourth surface), and a thermoplastic intermediate layer bonding the inner side surface of the outer pane to the outer side surface of the inner pane, wherein the composite pane has at least one solar radiation shielding coating between the outer pane and the inner pane that substantially reflects or absorbs light rays outside the visible spectrum of solar radiation, in particular infrared radiation, wherein the solar radiation shielding coating comprises the following layer sequence from the direction of the inner pane towards the outer pane: - a first dielectric module (M1), - a first silver layer (Ag1), - a second dielectric module (M2), - a second silver layer (Ag2), - a third dielectric module (M3), - a third silver layer (Ag3), - a fourth dielectric module (M4).

[0010] The silver layers (Ag1, Ag2, Ag3) of the solar radiation shielding coating according to the invention have layer thicknesses such that Ag2 > Ag1 > Ag3 relative to each other. Thus, the second silver layer Ag2 is the thickest silver layer, followed by the first silver layer Ag1, which is the thickness between the thickness of the second silver layer and the thickness of the third silver layer, and the third silver layer Ag3, which has the smallest layer thickness. The first silver layer Ag1 and the third silver layer Ag3 have a layer thickness such that 1.0 < Ag1 / Ag3 relative to each other, while the second silver layer Ag2 and the third silver layer have a layer thickness such that 1.2 < Ag2 / Ag3 < 2 relative to each other. This has proven to be particularly advantageous with regard to further improved optical and electrical properties of the composite pane, in particular with regard to the visually appealing blue reflection color of the coating at different reflection angles.

[0011] The structure of the layer sequence of the solar shading coating according to the invention is considered starting from the direction of the inner pane, where the fourth dielectric module is the layer of the solar shading coating closest to the inner surface of the outer pane (side II) and the first dielectric module is the layer of the solar shading coating closest to the outer surface of the inner pane (side III). The first dielectric module (M1), closest to the outer surface of the inner pane (side III), is followed in this order, starting from the inner pane towards the outer pane, by the first silver layer (Ag1), the second dielectric module (M2), the second silver layer (Ag2), the third dielectric module (M3), the third silver layer (Ag3) and the fourth dielectric module (M4). The fourth dielectric module is therefore the layer of the solar shading coating furthest from the outer surface of the inner pane (side III) and closest to the inner surface of the outer pane (side II). The silver layers are in each case arranged between the dielectric modules, i.e. between the dielectric layers or layer sequences. The solar shading coating is arranged between the inner surface (side II) of the outer pane and the outer surface (side III) of the inner pane and can be applied, for example, to one of the surfaces of the panes or can be integrated into a thermoplastic interlayer.

[0012] In other words, according to the present invention, the layer thickness of the second silver layer (Ag2) of the solar shielding coating is made larger than the layer thicknesses of the other two silver layers Ag1 and Ag3 located below and above it, respectively. The first silver layer Ag1 is arranged below the second silver layer Ag2 in the layer sequence of the solar shielding coating, and thus further from the outer pane, while the third silver layer Ag3 is arranged above the second silver layer Ag2 in the layer sequence, and thus closer to the outer pane. Moreover, the thickness of the first silver layer Ag1 is larger than the thickness of the third silver layer Ag3.

[0013] Surprisingly, it has been shown that the composite glass pane according to the invention has significantly improved electrical, optical and aesthetic properties compared to known composite glass panes with solar shading coatings, and at the same time has good energy properties; in particular, undesirable tints in the reflection of the composite pane can be minimized or even avoided. Furthermore, at most a very small angle-dependent change in the reflection color is achieved. Moreover, the composite pane according to the invention is compatible with a 14V / 42V DC / DC converter and can be heated, if required, with a supply voltage of 42V.

[0014] A composite pane comprises an outer pane and an inner pane, bonded together via a thermoplastic interlayer. The composite pane is intended to separate the interior from the exterior environment in a window opening, in particular in a vehicle window opening. In the context of the present invention, "inner pane" refers to the pane of the composite pane facing the interior, in particular the interior of a vehicle. "Outer pane" refers to the pane facing the exterior environment.

[0015] A composite pane has a top edge and a bottom edge and two side edges extending therebetween. The term "top edge" refers to the edge that is intended to face upward in the installed position. The term "bottom edge" refers to the edge that is intended to face downward in the installed position. In the case of a windshield, the top edge is also called the "roof edge" and the bottom edge is also called the "engine edge."

[0016] The outer pane and the inner pane in each case have an outer side surface and an inner side surface and a peripheral side edge extending therebetween. In the context of the present invention, the "outer side surface" refers to the main surface intended to face the exterior environment in the installed position. In the context of the present invention, the "inner side surface" refers to the main surface intended to face the interior in the installed position. The inner side surface of the outer pane and the outer side surface of the inner pane face each other and are joined to each other by a thermoplastic intermediate layer.

[0017] The solar shading coating of the composite pane according to the invention is preferably applied to one of the two pane surfaces facing the intermediate layer, i.e. the inner surface of the outer pane or the outer surface of the inner pane. Alternatively, the solar shading coating can be arranged in the thermoplastic intermediate layer, for example on a carrier film arranged between two thermoplastic bonding films. The solar shading coating is further suitable as an IR-reflective coating. In particular, the coating is applied to the entire surface of the pane, except for the peripheral area and optional local areas. These areas are intended to ensure the transmission of electromagnetic radiation through the composite pane as a communication, sensor or camera window and are therefore free of coating. The non-coated peripheral area has a width of, for example, up to 20 cm. This ensures that the coating is protected from corrosion and damage inside the composite pane by preventing it from coming into direct contact with the surrounding atmosphere.

[0018] In a preferred embodiment, the composite pane is a windshield and the solar shading coating is implemented as a transparent coating. A "transparent coating" is considered as a coating having an average transmission in the visible spectral range of at least 70%, preferably at least 72.5%, i.e. a coating that does not significantly limit vision through the pane. A transmission in the visible range of light of at least 72.5% is advantageous, especially when additional components of the pane limit the transmission. The coating is preferably suitable for heating with a supply voltage of 42V, but can also be used as a pure solar shading coating without a corresponding electrical connection for heating. Depending on the customer's requirements, other heating means, such as, for example, additional heating wires, can be provided in the composite pane, in which the solar shading coating does not have an electrical connection for contacting a voltage source. These further limit the transmission through the pane, so that the coating used must have a transmission of at least 72.5%. Very surprisingly, this criterion is met by the composite pane according to the invention, despite the many limitations imposed by optical, energy and electrical requirements.

[0019] Preferably, at least 80% of the pane surface is provided with a coating according to the invention.

[0020] When a first layer is arranged above a second layer, this means in the context of the present invention that the first layer is arranged further than the second layer in the direction of the outer pane. When a first layer is arranged below a second, this means in the context of the present invention that the second layer is arranged further than the first layer in the direction of the inner pane.

[0021] When the layer is based on a material, it consists largely of, in particular essentially of, this material in addition to any impurities or dopants.

[0022] A solar shading coating is a stack of layers or layer arrangements, in particular made up of thin layers, and comprises a number of silver layers. Each silver layer is in each case arranged between two dielectric layers or layer arrangements. These dielectric layers or layer arrangements are called dielectric modules. The term "dielectric module" therefore means a dielectric layer that can be formed from a single ply, i.e. a single dielectric layer, or from several plies of dielectric layers. The coating is therefore a stack of thin layers with n silver layers and (n+1) dielectric layers or layer arrangements, where n is a natural number and the silver layers and the dielectric layers or layer arrangements follow one another on the lower dielectric layer or layer arrangement.

[0023] The solar shading coating is a stack of thin layers, i.e. a layer sequence of thin individual layers, and preferably comprises at least four dielectric modules (M1, M2, M3 and M4), i.e. at least four dielectric layers. Each functional silver layer is arranged between two dielectric layers or layer sequences. The functional layers or layer sequences and the dielectric layers are arranged as follows: at least one dielectric layer is arranged in each case between two adjacent functional silver layers, between which no other functional silver layer is arranged, and at least one other dielectric layer is arranged above the top functional layer; and at least one other dielectric layer is arranged below the bottom functional layer.

[0024] The solar shading coating according to the invention has at least three silver layers, so that said natural number n is at least 3. The coating comprises at least the following layers or layer sequences, which are arranged in the given order starting from the inner pane towards the outer pane: a first dielectric layer or layer arrangement as module M1, - the first silver layer Ag1, - a second dielectric layer or layer arrangement as module M2, - the second silver layer Ag2, - a third dielectric layer or layer arrangement as module M3, - a third silver layer, Ag3, and - a fourth dielectric layer or layer arrangement as module M4.

[0025] The coating according to the invention may comprise further silver layers and dielectric modules arranged on the fourth dielectric module M4 (n>3). However, in a particularly preferred embodiment, said natural number n is exactly 3. The solar shading coating therefore preferably comprises exactly three silver layers, i.e. more than three and not more than three. A more complex layer structure is in principle not necessary to obtain the required specifications of the coating. The more complex the layer structure, the more complex the deposition. In this respect, it is a major advantage of the invention to obtain the desired properties of the coating with only three silver layers. However, in addition to the silver layers, other metal-containing layers can be present, which do not contribute significantly to the solar shading properties of the coating, but serve another purpose. This applies in particular to metal blocking layers having a geometric thickness of less than 1 nm. These metal blocking layers are preferably arranged between the silver layers and the dielectric modules.

[0026] The silver layer provides the solar shielding coating with the basic IR reflecting effect and the electrical conductivity required for heating the pane. In this context, the term "silver layer" refers to a layer formed on the basis of silver. The silver layer is based on silver. The silver layer preferably contains at least 90% by weight of silver, particularly preferably at least 99% by weight of silver, most particularly preferably at least 99.9% by weight of silver. The silver layer can have a dopant, for example palladium, gold, copper or aluminum.

[0027] The first dielectric module M1, the second dielectric module M2, the third dielectric module M3 and the fourth dielectric module M4 preferably have optical layer thicknesses relative to each other such that M2 / M1≧1.9, M2 / M3≧0.8 and M2 / M4≧2. A composite pane with a solar shading coating of this configuration further exhibits improved optical and aesthetic properties as well as a higher transmittance T in the visible range of light. L Shows.

[0028] In one embodiment of the present invention, all dielectric layers have a refractive index greater than 1.8, preferably greater than 1.9. In other words, all dielectric layers or layer sequences of the dielectric module are formed only by dielectric layers having a refractive index greater than 1.8. In this way, good results are obtained. The dielectric layers can be based, for example, on silicon nitride, mixed silicon metal nitrides (e.g. silicon-zirconium nitride (SiZrN), mixed silicon-aluminum nitride, mixed silicon-hafnium nitride, or mixed silicon-titanium nitride), aluminum nitride (AlN), tin oxide (SnO), manganese oxide (MnO), tungsten oxide (WO3), niobium oxide (Nb2O5), bismuth oxide (Bi2O3), titanium dioxide (TiO2), zinc oxide (ZnO), or mixed tin zinc oxide (SnZnO).

[0029] In the context of the present invention, the refractive index is in principle stated with respect to a wavelength of 550 nm. The optical thickness is the product of the geometric thickness and the refractive index (at 550 nm). The optical thickness of a layer sequence is calculated as the sum of the optical thicknesses of the individual layers. The refractive index can be determined, for example, by ellipsometry. Ellipsometers are commercially available, for example, from Sentech. The refractive index of a dielectric layer is preferably determined by first depositing it as a monolayer on a substrate and then measuring the refractive index by ellipsometry. To determine the refractive index of a dielectric layer sequence, the layers of the layer sequence are in each case deposited alone as a monolayer on a substrate and then the refractive index is determined by ellipsometry. In a preferred embodiment, a refractive index of at least 1.8 must be obtained for each of these individual layers. Dielectric layers with a refractive index of at least 1.8 and methods for their deposition are known to those skilled in the art of thin films. Preferably, physical vapor deposition methods, in particular magnetron sputtering, are used.

[0030] The materials mentioned herein can be deposited stoichiometrically, substoichiometrically or superstoichiometrically. The materials can have dopants, in particular aluminum, boron, zirconium or titanium. The dopants can give the essentially dielectric materials a certain electrical conductivity. Nevertheless, the skilled person will identify them as dielectric layers by function, as is customary in the field of thin layers. The materials of the dielectric layers are preferably 10 -4 The material of the silver layer preferably has an electrical conductivity (the inverse of the resistivity) of less than 10 4 It has electrical conductivity greater than S / m.

[0031] Preferably, the first dielectric module, the second dielectric module, the third dielectric module and / or the fourth dielectric module comprise a dielectric layer acting as an anti-reflection layer. In an advantageous embodiment, each dielectric module comprises a dielectric layer as an anti-reflection layer. The anti-reflection layer reduces the reflection of visible light and thus increases the transparency of the coated pane. The anti-reflection layer is based, for example, on silicon nitride (Si3N4), mixed silicon metal nitrides such as silicon zirconium nitride (SiZrN), aluminum nitride (AlN) or tin oxide (SnO). Furthermore, the anti-reflection layer can comprise a dopant. The anti-reflection layer preferably has a geometrical thickness of 5 nm to 100 nm, particularly preferably 6 nm to 60 nm. Silicon nitride is particularly preferred as an anti-reflection layer, since it has a high refractive index compared to oxides, so that the required thickness of the silicon nitride layer is relatively small. Furthermore, good color properties of the coating are obtained.

[0032] In an advantageous embodiment, the one or more dielectric modules have a first matching layer, preferably at least each dielectric module arranged under the silver layer. The first matching layer is preferably arranged on the anti-reflection layer. The first matching layer is preferably arranged directly under the first silver layer, in direct contact with the respective silver layer. This is particularly advantageous with respect to the crystallinity of the silver layer. In an advantageous embodiment, the one or more dielectric modules have a second matching layer, preferably each dielectric module arranged on the silver layer. The second matching layer is preferably arranged under the anti-reflection layer.

[0033] The first and / or second matching layer preferably comprises zinc oxide ZnO. The first and / or second matching layer also preferably comprises a dopant. The first and / or second matching layer may for example comprise aluminum doped zinc oxide (ZnO:Al). The zinc oxide is preferably deposited substoichiometrically with respect to oxygen, thereby avoiding the reaction of excess oxygen with the silver-containing layer. The geometric layer thickness of the first and second matching layers is preferably 5 nm to 20 nm, particularly preferably 8 nm to 20 nm. Zinc oxide has proven to be a preferred material for the matching layer due to its good smoothing properties, by means of which a high electrical conductivity of the adjacent silver layer can be advantageously obtained.

[0034] In an advantageous embodiment, the dielectric module or modules have at least one dielectric layer as a smoothing layer, preferably each dielectric module arranged between two silver layers has at least one dielectric layer as a smoothing layer, particularly preferably the bottommost first dielectric module has at least one dielectric layer as a smoothing layer. The at least one smoothing layer is arranged below the first matching layer, preferably between the antireflection layer and the first matching layer, if such a first matching layer is present. The smoothing layer is particularly preferably in direct contact with the first matching layer. The smoothing layer has the effect of optimizing the surface for the silver layer that is then applied on top, in particular a smoothing effect. A silver layer deposited on a smoother surface has a relatively high transmittance and at the same time a relatively low sheet resistance. The geometric layer thickness of the smoothing layer is preferably between 5 nm and 20 nm, particularly preferably between 7 nm and 12 nm. The smoothing layer preferably has a refractive index of less than 2.2.

[0035] The smoothing layer comprises at least one amorphous oxide. The oxide may be amorphous or partially amorphous (and therefore partially crystalline), but not completely crystallized. A non-crystalline smoothing layer has a low roughness and therefore forms an advantageously smooth surface for the layer applied on top of the smoothing layer. The non-crystalline smoothing layer further leads to an improved surface structure of the layer deposited directly on top of the smoothing layer, preferably this deposited layer being the first matching layer. The smoothing layer may comprise, for example, at least one oxide of one or more of the elements tin, silicon, titanium, zirconium, hafnium, zinc, gallium and indium. The smoothing layer preferably comprises an amorphous composite oxide. Most particularly preferably, the smoothing layer comprises mixed tin-zinc oxide (ZnSnO). The mixed oxide may comprise a dopant. The smoothing layer may comprise, for example, antimony-doped mixed tin-zinc oxide. The mixed oxide preferably has a substoichiometric oxygen content. The tin content is preferably from 10% to 40% by mass, and particularly preferably from 12% to 35% by mass.

[0036] In an advantageous embodiment, the solar-shading coating comprises one or more blocking layers. Preferably, at least one blocking layer is associated with at least one silver layer, particularly preferably with each silver layer. The blocking layer is in direct contact with the silver layer and is arranged directly above or directly below the silver layer. That is to say, no other layers are arranged between the silver layer and the associated blocking layer. The blocking layer can also be arranged in each case directly above and directly below the silver layer. The blocking layer preferably comprises niobium, titanium, nickel, chromium and / or alloys thereof, particularly preferably nickel-chromium alloys. The geometric layer thickness of the blocking layer is preferably 0.1 nm to 1.5 nm, particularly preferably 0.1 nm to 1.0 nm. The blocking layer located directly below the silver layer serves in particular to stabilize the silver layer during temperature treatment and improves the optical quality of the solar-shading coating. The blocking layer immediately above the silver layer prevents the delicate silver layer from contacting an oxidizing reactive atmosphere during deposition of the next layer by reactive cathode sputtering, for example during deposition of a second matching layer.

[0037] If the layer is based on a material, it consists mostly of this material, in addition to impurities or dopants. If a first layer is placed on top of a second layer, this means in the context of the present invention that the first layer is placed further away from the substrate to which the coating is applied than the second layer. If a first layer is placed below a second layer, this means in the context of the present invention that the second layer is placed further away from the substrate than the first layer. If a first layer is placed above or below a second layer, this does not necessarily mean in the context of the present invention that the first and second layers are located in direct contact with each other. Unless expressly excluded, one or more other layers may be placed between the first and second layers.

[0038] In an advantageous embodiment, a dielectric module is arranged, which comprises, in each case between two adjacent silver layers, the following dielectric layer sequence:

[0039] - antireflection layers based on silicon nitride, mixed silicon-metal nitrides such as silicon nitride-zirconium nitride, aluminium nitride and / or tin oxide:

[0040] smoothing layers based on oxides of one or more of the elements tin, silicon, titanium, zirconium, hafnium, zinc, gallium and indium:

[0041] a first matching layer and a second matching layer based on zinc oxide; and -Optionally, a blocking layer based on niobium, titanium, nickel, chromium and / or alloys thereof. No particular order of layers is required. The anti-reflection and matching layers based on the preferred materials above are preferably arranged below the bottom silver layer and above the top silver layer. In a preferred embodiment comprising three silver layers, the bottom silver layer is the first silver layer and the top silver layer is the third silver layer.

[0042] The dielectric modules preferably have a geometric thickness in each case between 10 nm and 100 nm, particularly preferably between 20 nm and 90 nm, for example between 70 nm and 85 nm. The optical thickness of the module is obtained by multiplying the geometric thickness of the dielectric module by the refractive index of each layer. The optical thickness of the dielectric module is between 20 nm and 240 nm, preferably between 40 nm and 200 nm.

[0043] The geometric thickness of each functional silver layer of the solar-shading coating is preferably 5 nm to 25 nm. The total geometric layer thickness of all functional silver layers of the solar-shading coating is preferably 20 nm to 75 nm, particularly preferably 25 nm to 60 nm. In these ranges for the thickness of the functional layers and the total thickness of all functional silver layers, particularly good results are obtained in terms of solar-shading function and transparency.

[0044] The first silver layer (Ag1) preferably has a geometric thickness of 7 nm to 14 nm, the second silver layer (Ag2) preferably has a geometric thickness of 7 nm to 16 nm and the third silver layer (Ag3) preferably has a geometric thickness of 6 nm to 13 nm. Layer thicknesses within these ranges have proven advantageous for obtaining a sheet resistance of the solar shading coating of 1.0 Ω / sq to 1.5 Ω / sq, which is particularly suitable for using the coating with a supply voltage of 42 V.

[0045] The solar shading coating according to the invention has IR reflecting properties so that it acts as a solar shading coating that reduces heating inside the vehicle by reflecting thermal radiation. The TTS value of the coated composite pane is preferably less than 50%, particularly preferably less than 45%. The TTS value refers to the total solar energy transmitted, measured according to ISO 13837. It is a measure of thermal comfort. The coating can also be used as a heating coating when it is electrically contacted so that an electric current flows through it, and the coating can be heated.

[0046] The outer and inner panes are preferably made of glass, in particular soda-lime glass, which is common for window panes. However, the panes may in principle also be made of other types of glass (e.g. borosilicate glass, quartz glass, aluminosilicate glass, etc.) or transparent plastics (e.g. polymethylmethacrylate or polycarbonate). The thickness of the outer and inner panes may vary over a wide range. Preferably, panes are used having a thickness in the range of 0.8 mm to 5 mm, preferably 1.4 mm to 2.9 mm, for example standard thicknesses of 1.6 mm or 2.1 mm.

[0047] The outer pane, inner pane, and thermoplastic interlayer may be transparent and colorless, but may also be tinted or colored. The coloring of the outer pane, inner pane, and thermoplastic interlayer is selected depending on the desired application of the composite pane. When the composite pane is used as a windshield, high transmission is desired in the visible range of the light spectrum, and dark tinting of the components is not used. In one embodiment as an automobile windshield, the total transmission through the composite glass is greater than 70%, based on Illuminant A. The term "total transmission" is based on the process for testing the light transmission of automobile windows specified by ECE-R 43, Annex 3, §9.1. The outer pane and inner pane may be unprestressed, partially prestressed, or prestressed, independently of each other. If at least one of the panes is prestressed, this may be thermal or chemical prestressing.

[0048] Suitable glass panes include Saint-Gobain glass panes known under the trade names Planiclear® and Planilux® (in each case clear glass), VG10, VG20, VG40 or TSANx, TSA3+, TSA4+, the VG series glasses being grey-coloured glasses and the TSA series glasses being green-coloured glasses. In a preferred embodiment, the composite pane is intended as an automobile windshield, where at least the thermoplastic interlayer, the inner pane and the outer pane are clear.

[0049] The composite pane is preferably curved in one or more spatial directions, as is customary for automobile panes, with typical radii of curvature in the range of about 10 cm to 40 m, although the composite pane can also be flat, for example when intended as a pane for a bus, train, or tractor.

[0050] The inner surface of the outer pane and the outer surface of the inner pane face each other and are bonded to each other by a thermoplastic intermediate layer. The thermoplastic intermediate layer is formed by one or more thermoplastic films. Here, in the resulting composite pane, the individual films in the resulting intermediate layer may no longer be distinguishable from each other. The thermoplastic film preferably contains polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), and / or mixtures thereof and / or copolymers thereof, particularly preferably polyvinyl butyral. The film is preferably based on the above-mentioned materials, but may contain other components, such as plasticizers, colorants, IR or UV absorbers.

[0051] The thermoplastic interlayer contains at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or polyurethane (PU), or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The thickness of the interlayer is preferably 0.2 mm to 2 mm, particularly preferably 0.3 mm to 1 mm. The individual polymer films of the interlayer, in particular the PVB films, preferably have a thickness of about 0.2 mm to 1 mm, for example 0.38 mm, 0.76 mm or 0.81 mm. Other properties of the composite glass pane can be influenced by the thickness of the film. For example, a thicker PVB film improves the soundproofing, increases the penetration resistance of the composite glass pane, especially when it contains an acoustically active core, and also increases the protection against ultraviolet rays (UV protection).

[0052] According to the invention, the solar-shading coating is arranged between the outer pane and the inner pane. In a preferred embodiment, the solar-shading coating is applied to the inner surface (side II) of the outer pane. In this way, the solar-shading coating is protected from the effects of weathering in the laminate of the composite pane. It is advantageous, particularly with regard to a good solar-shading effect, to arrange the solar-shading coating as far outward as possible, i.e. as close as possible to the outer surface of the outer pane. This is further optimized by using a transparent, untinted outer pane.

[0053] In another possible embodiment, the solar-shading coating is embedded in the thermoplastic interlayer. The solar-shading coating can be applied on top of a thermoplastic film. In a preferred embodiment, the solar-shading coating is applied to a carrier film that is arranged in the manufacture of the composite pane, for example between two thermoplastic films that serve to form an interlayer. The integration of the solar-shading coating via the carrier film is advantageous with regard to simple prefabrication and the provision of a carrier film with a solar-shading coating. The film of the thermoplastic interlayer, arranged between the solar-shading coating and the outer pane, is preferably transparent and colorless. The thermoplastic interlayer of the composite pane comprises a carrier film thereon, i.e. on the surface facing the outer pane, with a solar-shading coating. The carrier film preferably comprises or is made of polyethylene terephthalate (PET) and has a thickness of 20 μm to 100 μm, for example approximately 50 μm. However, the carrier film may also be made of other suitable plastics.

[0054] In another preferred embodiment, the solar shading coating is applied to the outer surface III of the inner pane. In this case, the outer pane and the thermoplastic intermediate layer are preferably transparent and colorless. This embodiment is advantageous depending on the location of the opaque mask printing in the edge area, allowing greater flexibility with regard to the printing inks used for the mask printing.

[0055] When the solar shading coating is provided as a heating coating, the coating is electrically connected in a manner known per se to an external voltage source and the coating is heated through the application of a voltage. The electrical contact is effected via a suitable connecting cable, e.g. a foil conductor, which is preferably connected to the solar shading coating via a so-called busbar, e.g. a strip of conductive material or a conductive imprint.

[0056] Preferably, at least two busbars are attached to the solar shading coating and conductively connected thereto. These at least two busbars are preferably attached along opposite edges of the composite pane and can be conductively connected to opposite poles of a voltage source for heating the pane. The coating area between the busbars is thereby electrically heatable. In a possible embodiment of the invention, three busbars are applied, one busbar each extending parallel to the horizontal edges and the third busbar protruding from the roof edge towards the centre of the pane. The first busbar is located adjacent to the roof edge, while the second busbar is adjacent to the engine edge, both busbars extending parallel to these horizontal side edges. In a particularly preferred embodiment, the shape of the busbar or busbars is adapted to any decoated area for the sensor window, which serves for the mounting of the sensor. The busbars have a thickness of 5 μm to 20 μm, preferably 8 μm to 15 μm. The width of the busbars is 0.5 mm to 30 mm, preferably 1 mm to 20 mm.

[0057] In another preferred embodiment, the solar shading coating is not intended to be connected to a voltage source. Optionally, other means for heating the pane are provided, for example in the form of a heating wire attached between the outer surface (side III) of the inner pane and the inner surface (side II) of the outer pane. The heating wire is preferably inserted in the thermoplastic intermediate layer. The heating wire may optionally be electrically insulated. This allows contact between the wire and the coating while avoiding short circuits. Thus, the bonding film of the thermoplastic intermediate layer with the heating wire can be attached to the wire facing the coating. If the wire is not insulated, the heating wire should be placed on the side of the bonding film opposite the coating. The insulation of the wire is obtained, for example, by a polymer-containing sheath: particularly preferably this comprises polyethylene, polyvinyl chloride, polytetrafluoroethylene, polyester, polycarbonate, rubber, silicone rubber, polyamide, polyurethane, and / or mixtures and / or copolymers thereof.

[0058] The minimum distance between adjacent heating wires is 2 mm, while the maximum distance between adjacent heating wires is 35 mm.

[0059] The heating wire comprises tungsten, copper, nickel, manganese, aluminum, silver, chromium and / or iron and / or mixtures thereof and / or alloys thereof, preferably tungsten or copper, particularly preferably tungsten.

[0060] The heating wires have a thickness between 5 μm and 160 μm. The thickness depends in particular on the material used for the wire. Tungsten wires are preferably used with a thickness between 10 μm and 80 μm, while copper wires have a thickness preferably between 60 μm and 150 μm.

[0061] The heating wire is contacted at its ends via multiple conductors, preferably two. Depending on the path of the heating wire, for example, meandering or zigzag, different contact configurations can be selected. In the case of a continuously meandering wire, the voltage must, for example, be selectively applied only to both ends of the wire.

[0062] Preferably, the composite glass pane has an external energy reflection RE>30%. The calculation of the energy value RE is performed according to the ISO 9050 standard.

[0063] An opaque masking layer, for example in the form of a screen print, is preferably applied to the edge area of ​​the pane, such that the screen print surrounds the field of view of the pane or forms its outer edge. Busbars and conductors, as well as optionally provided edge areas free of coating, are preferably covered by the masking print and are thus visually hidden. The opaque screen print may be applied on any flat surface of the composite glass pane.

[0064] The invention further relates to a method for producing a composite pane according to the invention having a solar shading coating, said method comprising the following steps: a) applying a solar protection coating to the inner surface II of the outer pane or to the outer surface III of the inner pane or incorporating a solar protection coating into the thermoplastic interlayer; b) producing a stack of layers including at least an outer pane, a thermoplastic intermediate layer, and an inner pane, in that order; and c) bonding the stack of layers including at least an outer pane, a thermoplastic intermediate layer, and an inner pane to form a composite pane.

[0065] The outer and inner panes are bonded together to form a composite glass, preferably after applying a solar blocking coating.

[0066] Solar shading coatings are able to withstand high thermal loads and therefore can also withstand temperature treatment or bending of the pane, typically at temperatures above 600° C., without damage.

[0067] The individual layers of the solar protection coating can be deposited by methods known per se, preferably by magnetron-enhanced cathodic sputtering, and can be built up in suitable layer thicknesses and layer sequences. Cathodic sputtering can be carried out in a protective gas atmosphere, for example in an argon protective gas atmosphere, or in a reactive gas atmosphere, for example with the addition of oxygen or nitrogen. However, the individual layers can also be applied by other suitable methods known to the person skilled in the art, for example by vapor deposition or chemical vapor deposition.

[0068] The thermoplastic interlayer may be provided in the form of a thermoplastic film. However, the thermoplastic interlayer may also be provided in the form of a plurality of films, e.g., two or more thermoplastic films, optionally with an additional carrier film. Application of the solar shading coating onto the thermoplastic interlayer only involves application of the solar shading coating to one of the films, e.g., to the carrier film. When joining the panes to form the composite glass, the carrier film with the solar shading coating disposed thereon is preferably disposed between the two thermoplastic films, with the surface of the solar shading coating facing the outer pane.

[0069] Electrical contact of the conductive layers via bus bars or other suitable electrical conductors is made prior to lamination of the composite panes.

[0070] Any imprints that may be present, such as opaque masking prints or printed bus bars for electrical contact of the solar shielding coating, are preferably applied by screen printing.

[0071] The bonding of the outer and inner panes via the thermoplastic interlayer to form a composite pane is preferably carried out by lamination under the action of heat, vacuum and / or pressure. Methods known per se for manufacturing composite panes may be used. During the lamination process, a heated, flowable thermoplastic material flows around the solar protection coating, establishing a stable bond and encapsulating the latter in the interlayer, protecting it from damage and environmental influences.

[0072] For example, the so-called autoclave process can be carried out at high pressures of about 10 bar to 15 bar and at temperatures of 130° C. to 145° C. for about 2 hours. The vacuum bag or vacuum ring process, known per se, operates, for example, at about 200 mbar and 80° C. to 110° C. The outer pane, the thermoplastic intermediate layer and the inner pane may also be pressed between at least one pair of rollers in a calender, thereby forming the pane. Systems of this type are known for the manufacture of panes and usually have at least one heating tunnel upstream of the pressing unit. The temperature during the pressing operation is, for example, in the range of 40° C. to 150° C. The combination of calendering and autoclave processes has proven to be particularly effective in practice. Alternatively, vacuum laminators can also be used. These consist of one or more heatable and evacuable chambers in which the panes are laminated, for example, within about 60 minutes, at reduced pressures of 0.01 mbar to 800 mbar and at temperatures of 80° C. to 170° C.

[0073] The invention further comprises the use of the composite panes according to the invention with a solar shading coating in land, air or water transport vehicles, in particular in motor vehicles, e.g. as windscreens, rear windows, side windows and / or roof panels, and also as functional individual components, and in buildings.

[0074] All standards mentioned refer to the versions in effect on the filing date.

[0075] The various embodiments of the invention may be implemented individually or in any combination. In particular, the features described above and below may be used not only in the combinations shown, but also in other combinations or alone, without departing from the scope of the invention, unless the exemplary embodiments and / or their features are expressly mentioned only as alternatives or are mutually exclusive.

[0076] The present invention will be described in more detail below with reference to the drawings. It should be noted that various aspects are described and each can be used individually or in combination. In other words, any aspect can be used with various embodiments of the present invention unless expressly presented as a pure alternative.

[0077] The drawings are simplified schematic views and are not to scale. The drawings are not intended to limit the invention. [Brief description of the drawings]

[0078]

Figure 1

[0079]

Figure 2

[0080]

Figure 3

[0081]

Figure 4

[0082]

Figure 5

[0083] Figure 1 shows a cross-sectional view of an embodiment of a composite pane 100 according to the invention, having a solar radiation shielding coating 4. The composite pane 100 includes an outer pane 1 and an inner pane 2 bonded to each other via a thermoplastic intermediate layer 3. The composite pane 100 can be provided, for example, as the front windshield of a passenger vehicle, with the outer pane 1 facing the external environment and the inner pane 2 facing the interior of the vehicle. The outer pane 1 has an outer side surface (I) and an inner side surface (II). The inner pane 2 has an outer side surface (III) and an inner side surface (IV). The outer side surfaces (I) and (III) face the external environment; the inner side surfaces (II) and (IV) face the interior of the vehicle. The inner side surface (II) of the outer pane 1 and the outer side surface (III) of the inner pane 2 face each other. In this embodiment, the solar radiation shielding coating 4 according to the invention is arranged on the inner side surface (II) of the outer pane 1. The solar radiation shielding coating 4 preferably extends over the entire inner side surface (II), excluding a region without a circumferential frame-shaped coating, for example, a region without a circumferential frame-shaped coating having a width of 8 mm. The region without the coating can then be hermetically sealed by bonding to the thermoplastic intermediate layer 3. Thus, the solar radiation shielding coating 4 is advantageously protected from damage and corrosion. According to the invention, the solar radiation shielding coating 4 includes at least three functional silver layers, each having a geometric layer thickness of 5 nm to 20 nm, and each functional silver layer is arranged between dielectric modules, for example, layers of silicon nitride. The silver layers (Ag1, Ag2, Ag3) of the solar radiation shielding coating according to the invention have layer thicknesses such that 1.0 < Ag1 / Ag3 and 1.2 < Ag2 / Ag3 < 2 with respect to each other, where Ag2 > Ag1 > Ag3. The dielectric modules (M1, M2, M3, M4) have optical layer thicknesses such that M2 / M1 ≧ 1.9, M2 / M3 ≧ 0.8, and M2 / M4 ≧ 2 with respect to each other. The structure of the solar radiation shielding coating 4 according to the invention will be explained in more detail below using Figure 4 and the examples and comparative examples described therein. The solar radiation shielding coating 4 reduces the heating of the interior of the vehicle and the inner pane 2 by reflection of infrared radiation. An energy reflection RE > 30%, a total solar transmittance TTS < 45%, and a light transmittance TL > 72.5% can be achieved.The solar shading coating 4 according to the invention also simultaneously provides good optical and aesthetic properties of the composite pane 100 in addition to improved thermal comfort. The sheet resistance of the solar shading coating 4 is between 1.0 Ω / sq and 1.5 Ω / sq, so that the coating has good compatibility with 14V / 42V DC / DC converters.

[0084] Figure 2 shows a cross-sectional view of another embodiment of a composite pane 100 according to the invention, with a solar-shading coating 4. In contrast to Figure 1, the solar-shading coating 4 is not arranged on the inner surface (II) of the outer pane 1, but on a carrier film 5 in the intermediate layer 3. The carrier film 5 preferably comprises or is made of polyethylene terephthalate (PET) and has a thickness of, for example, 50 μm. The solar-shading layer 4 according to the invention comprises a layer structure, which is explained in more detail with respect to Figure 4. The carrier film 5 provided with the solar-shading coating 4 is arranged between a first thermoplastic film 3a and a second thermoplastic film 3b. In the resulting composite pane, the thermoplastic films 3a and 3b and the carrier film 5 form the thermoplastic intermediate layer 3. The thermoplastic films 3a and 3b preferably comprise or are made of PVB and have a layer thickness of, for example, 0.38 mm. The carrier film 5 is somewhat smaller than the outer pane 1, the inner pane 2 and the thermoplastic films 3a and 3b. The carrier film 6 is arranged in the composite such that the carrier film 5 does not extend to the lateral edges of the composite pane. As a result, the carrier film 5 is peripherally surrounded, for example with a width of about 8 mm, by the thermoplastic films 3a and 3b in the edge region of the composite pane. The solar shading coating 4 on the carrier film 5 is thus advantageously protected against damage, in particular against corrosion.

[0085] FIG. 3 shows a cross-sectional view of another embodiment of the composite pane 100 according to the invention, having a solar radiation shielding coating 4. In contrast to FIG. 1, the solar radiation shielding coating 4 is arranged on the outer side surface (III) of the inner pane 2, rather than on the inner side surface (II) of the outer pane 1. The solar radiation shielding coating 4 is not applied to the peripheral region of the outer side surface (III). Also in this embodiment, the solar radiation shielding coating 4 is advantageously protected from damage and corrosion. Otherwise, this embodiment corresponds to the design shown in FIG. 1.

[0086] FIG. 4 shows a schematic structure of the solar radiation shielding coating 4 according to the invention. In the illustrated embodiment, the solar radiation shielding coating 4 is applied to the inner surface III of the inner pane 2 as a substrate. The illustrated solar radiation shielding coating 4 includes three transparent functional silver layers Ag1, Ag2, and Ag3, which are particularly infrared reflecting layers. The functional silver layers have a certain thickness relative to each other; specifically, they are made such that the following applies to the relative geometric layer thicknesses: Ag2>Ag1>Ag3, 1.0<Ag1 / Ag3, and 1.2<Ag2 / Ag3<2. In other words, the layer thickness of the third silver layer Ag3, which is arranged closest to the outermost pane 1, is thinner than the layer thickness of the first silver layer Ag1, which is closest to the inner pane 2, while the second silver layer Ag2 is the silver layer that is located between the first silver layer Ag1 and the third silver layer Ag3 in the layer arrangement and has the largest layer thickness. The silver layers can be deposited, for example, by cathode sputtering in an argon atmosphere.

[0087] The dielectric modules M1, M2, M3 and M4 comprising dielectric layers are arranged above, below and between the silver layers Ag1, Ag2 and Ag3, respectively. These dielectric modules (M1, M2, M3, M4) preferably have optical layer thicknesses M2 / M1≧1.9, M2 / M3≧0.8 and M2 / M4≧2 relative to one another. Thus, the dielectric module M1 is arranged directly on the inner side III of the inner pane 2, below the first silver layer Ag1; the second dielectric module M2 is arranged above the first silver layer Ag1. The first dielectric module M1 can be structured, for example, starting from the inner pane 2, as a layer sequence of silicon nitride, ZnSnOx and ZnO layers. The silicon nitride layer can be deposited from silicon nitride in a nitrogen-containing atmosphere; the zinc oxide layer can be deposited from zinc oxide in an oxygen-containing atmosphere.

[0088] The solar shielding coating 4 comprises at least one blocking layer; particularly preferably, each functional silver layer Ag1, Ag2, Ag3 is located in direct contact with at least one blocking layer B1, B2 and B3, as shown. According to the invention, the blocking layers preferably comprise or are made of at least nickel, chromium or alloys thereof and / or titanium chromium. The blocking layer B (B1, B2, B3) is preferably arranged between the at least one functional silver layer and the at least one dielectric layer. The blocking layer B protects the functional layers during heating, in particular during the manufacture of the composite pane according to the invention.

[0089] The invention will now be described with reference to the following inventive and non-inventive comparative examples.

[0090] Working Example

[0091] All optical, aesthetic and energy properties of the composite panes according to the examples and comparative examples were measured in the laminated state. In the examples and comparative examples, a solar shading coating 4 was applied to the outer face III of a transparent inner pane 2 (example Planiclear) according to figure 4 and laminated with a thermoplastic intermediate layer 3 and an outer pane 1 according to the structure of figure 3. In the intermediate layer, a colorless PVB film was used. The examples and comparative examples have the same basic structure described, but differ in the solar shading coating used.

[0092] Examples 1-5 according to the invention and Comparative Examples 1-3 not according to the invention were manufactured as composite panes (vehicle windshields) having the indicated solar shielding coatings.

[0093] For each example and comparative example, the stack structure (layers and layer thicknesses) of the solar shielding coating and the optical properties of the coating in the finished composite pane are given.

[0094] The layer sequences and layer thicknesses of the solar shielding coatings according to Examples 1-5 according to the invention and Comparative Examples 1-3 are shown and compared therewith and are presented in Table 1. The relative layer thicknesses of the silver layers and the dielectric modules as well as the values ​​of the optical, electrical and energy properties for Examples 1-5 according to the invention and Comparative Examples 1-3 not according to the invention are reported in Table 2. All layer thicknesses of the silver layers and the layers of the modules are shown as geometric layer thicknesses. The relative layer thicknesses of the silver layers, shown as thickness ratios Ag2 / Ag1, Ag2 / Ag3 and Ag1 / Ag3, refer to the geometric layer thicknesses. For the relative layer thicknesses of the dielectric modules, shown as thickness ratios M2 / M1, M2 / M3 and M2 / M4, the optical thicknesses were used.

[0095] Abbreviation RE Energy Reflection [%] TL Visible light transmittance [%] TTS Total transmitted thermal radiation [%] TE Total transmitted energy [%] RL 8° Visible reflection at 8° viewing angle [%] RL 60° Visible reflection at a viewing angle of 60° [%] a * , b * Color coordinates in the CIE color space (International Commission on Illumination), measured in reflection at angles of 60° and 8° respectively Δa * , Δb * The difference in color coordinates when measured in reflection at 60° and at 8° Color R * The color impression of the external reflected color in each case, as perceived by an observer of the composite pane, at 60° and at 8° reflection Rsq Sheet resistance of solar shielding coating [Ω / sq]

[0096] Light transmittance (TL) and reflectance (RL) values ​​are based on Illuminant A, which by definition is based on the relative irradiance distribution of a perfect radiator at 2856 Kelvin.

[0097] [Table 1]

[0098] [Table 2]

[0099] According to the invention, a composite pane with a solar shading coating constructed according to the invention is provided, which composite pane is successfully improved and further optimized in terms of energy and electrical properties, thermal and visual comfort, and at the same time in terms of aesthetic appearance, compared to known composite panes with a solar shading coating. A total transmitted thermal radiation (TTS) of less than 45% is obtained, so that the corresponding frequently required customer specifications can be met. Furthermore, a light transmission TL ≥ 72.5% is obtained, so that the composite pane can be used as a windshield; and when combined with a common wire heater, the statutory requirement TL ≥ 70% is obtained. Furthermore, an optimal aesthetic appearance without undesirable hues in the reflection of the composite pane is obtained. In particular, undesirable red, yellow, purple and green reflections or haze of the composite pane can be avoided. A substantially constant desired color reflection of the composite pane can be obtained, regardless of the viewing angle. Furthermore, the solar shading coating according to the invention has a sheet resistance of 1.0 Ω / sq to 1.5 Ω / sq, and is therefore well suited for heating with a supply voltage of 42 V.

[0100] To further illustrate the advantages of the silver layer thickness combinations, exemplary optical and energy properties of the silver coatings, with the respective thickness ratios shown, are reported in Table 3. The thickness of the dielectric module and the order of the layers in the layer stack are the same in each case.

[0101] [Table 3]

[0102] As can be seen in Table 3, good optical and energy properties and an attractive color can only be obtained using the thickness ratios of the silver layers according to the invention, which have the following provisions regarding the thickness of the silver layers: Ag2 > Ag1 > Ag3. Layers having the following properties are considered acceptable: TL ≧ 72.5%, TTS ≦ 45%, RL60° ≦ 17.5%. Furthermore, the color coordinates should be as small as possible, and particularly preferably, should have a negative sign. From Table 2, it can be seen that a desirable blue reflection color is obtained at both a viewing angle of 8° and a viewing angle of 60° only for the thickness combinations according to the invention, which comprise Ag2 > Ag1 > Ag3, 1.0 > Ag1 / Ag3, and 1.2 < Ag2 / Ag3 < 2. In this color range, a blue color tone that is particularly well-received by customers is obtained. a from -5.0 to 0 * The value of R 60°, and b from -8.0 to 0 * The value of R 60° is also particularly advantageous.

[0103] Figure 5 shows an exemplary embodiment of the method according to the invention with reference to a flowchart comprising the following steps. I Providing an outer pane 1, an inner pane 2, and at least one thermoplastic film (for forming the thermoplastic intermediate layer 3); II Applying a solar radiation shielding coating 4 according to the invention to the inner side surface II of the outer pane 1 or the outer side surface III of the inner pane 2, for example, by cathodic sputtering; III Optionally: applying a bus bar to the solar radiation shielding coating 4; IV Bonding the inner side surface II of the outer pane 1 and the outer side surface III of the inner pane 2 via the thermoplastic intermediate layer 3 to form a composite pane 100

[0104] In one embodiment, a glass pane is used as the outer pane 1 and as the inner pane 2. In a preferred embodiment of the method, a solar-shading coating 4, having at least three functional silver layers Ag1, Ag2, and Ag3, and at least four dielectric modules M1, M2, M3, and M4, is applied to the outer surface III of the inner pane 2. It is preferably applied by magnetron-enhanced cathode sputtering. If the pane is heated via the solar-shading coating 4, busbars and electrical connection cables are provided on the solar-shading coating 4 before laminating the panes. This electrical connection cable allows electrical contact of the coatings. The joining of the outer pane 1 and the inner pane 2 via the interlayer 3 to form a composite glass is preferably performed after the solar-shading coating 4 has been applied. The present disclosure includes the following aspects. <Aspect 1> A composite pane (100) including an outer pane (1) having an outer side surface (I) and an inner side surface (II), an inner pane (2) having an outer side surface (III) and an inner side surface (IV), and a thermoplastic intermediate layer (3), wherein the thermoplastic intermediate layer (3) bonds the inner side surface (II) of the outer pane (1) to the outer side surface (III) of the inner pane (2), the composite pane (100) has at least one solar radiation shielding coating (4) between the outer pane (1) and the inner pane (2), the solar radiation shielding coating (4) has the following layer arrangement starting from the inner pane (2) and facing the outer pane (1): - A first dielectric module (M1), - A first silver layer (Ag1), - A second dielectric module (M2), - A second silver layer (Ag2), - A third dielectric module (M3), - A third silver layer (Ag3), - A fourth dielectric module (M4), and includes, the silver layers (Ag1, Ag2, Ag3) have a geometric layer thickness of Ag2 > Ag1 > Ag3 with respect to each other, and the silver layers (Ag1, Ag2, Ag3) of the solar radiation shielding coating have a relative geometric layer thickness of 1.0 < Ag1 / Ag3 and 1.2 < Ag2 / Ag3 < 2, composite pane (100). <Aspect 2> The composite pane (100) according to Aspect 1, wherein the dielectric modules (M1, M2, M3, M4) have a relative optical layer thickness of M2 / M1 ≥ 1.9, M2 / M3 ≥ 0.8, and M2 / M4 ≥ 2. <Aspect 3> The composite pane (100) according to Aspect 1 or 2, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3), and / or the fourth dielectric module (M4) have at least one dielectric layer based on silicon nitride. <Aspect 4> The composite pane (100) according to any one of Aspects 1 to 3, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3), and / or the fourth dielectric module (M4) include at least one first dielectric layer based on silicon nitride and at least one second dielectric layer based on zinc oxide. <Aspect 5> 5. The composite pane according to any of aspects 1 to 4, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3), and / or the fourth dielectric module (M4) comprise at least one first dielectric layer based on silicon nitride, at least one second dielectric layer based on zinc oxide, and at least one third dielectric layer based on mixed tin-zinc oxide. <Aspect 6> 6. The composite pane according to any of the preceding aspects, wherein the solar shielding coating (4) comprises at least one metal blocking layer (B1, B2, B3) above and / or below the silver layer (Ag1, Ag2, Ag3), respectively, having a geometric thickness of less than 1 nm. <Aspect 7> 7. The composite pane of any of aspects 1-6, wherein the first silver layer (Ag1), the second silver layer (Ag2), and the third silver layer (Ag3) each have a geometric thickness of 5 nm to 25 nm. <Aspect 8> The first silver layer (Ag1) has a geometric thickness of 7 nm to 14 nm, The second silver layer (Ag2) has a geometric thickness of 7 nm to 16 nm, The third silver layer (Ag3) has a geometric thickness of 6 nm to 13 nm. 8. The composite pane of embodiment 7. <Aspect 9> The composite pane according to any one of aspects 1 to 9, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3), and the fourth dielectric module (M4) each have a geometric thickness of 10 nm to 100 nm, preferably 20 nm to 90 nm, and particularly preferably 70 nm to 85 nm. <Aspect 10> A composite pane according to any of the preceding aspects, wherein the solar shielding coating (4) is applied to the exterior surface (III) of the inner pane (1). <Aspect 11> 11. The composite pane according to any of the preceding aspects, wherein the solar shielding coating (4) has at least two busbars via which the solar shielding coating (4) can be connected to a voltage source. <Aspect 12> 11. The composite pane according to any of the preceding aspects, wherein a heating wire is present between the outer surface (III) of the inner pane (2) and the inner surface (II) of the outer pane (I). <Aspect 13> 13. The composite pane according to any of the preceding aspects, wherein the solar shielding coating (4) comprises exactly three silver layers (Ag1, Ag2, Ag3). <Aspect 14> at least, (a) applying a solar shading coating (4) to the interior surface (II) of the outer pane (1) or the exterior surface (III) of the inner pane (2) or incorporating a solar shading coating (4) in a thermoplastic intermediate layer (3); (b) producing a stack of layers comprising at least the outer pane (1), the thermoplastic intermediate layer (3), and the inner pane (2), in that order; and (c) bonding a stack of layers including at least the outer pane (1), the thermoplastic intermediate layer (3), and the inner pane (2) to form a composite pane (100), A method for producing a composite pane (100) according to any one of the first to thirteenth embodiments. <Aspect 15> Use of a composite pane (100) according to any of the embodiments 1 to 13 in a motor vehicle, preferably as a windshield, rear window, side window and / or roof panel, particularly preferably as a motor vehicle windshield. [Explanation of symbols]

[0105] 1 outer pane, 2 inner pane, 3 thermoplastic intermediate layer, 3a first thermoplastic film, 3b second thermoplastic film, 4 solar shielding coating, 5 carrier film, I 1 outer surface, II 1 inner surface, III 2 outer surface, IV 2 inner surface, Ag1 first silver layer, Ag2 second silver layer, Ag3 third silver layer, M1 first dielectric module, M2 second dielectric module, M3 third dielectric module, M4 fourth dielectric module, B blocking layer, B1 first blocking layer, B2 second blocking layer, B3 third blocking layer

Claims

1. A composite pane (100) comprising an outer pane (1) having an outer surface (I) and an inner surface (II), an inner pane (2) having an outer surface (III) and an inner surface (IV), and a thermoplastic intermediate layer (3), the thermoplastic intermediate layer (3) connects the inner surface (II) of the outer pane (1) to the outer surface (III) of the inner pane (2); The composite pane (100) has at least one solar shielding coating (4) between the outer pane (1) and the inner pane (2); The solar shielding coating (4) is formed in the following layer sequence starting from the inner pane (2) towards the outer pane (1): a first dielectric module (M1), a first silver layer (Ag1), a second dielectric module (M2), - a second silver layer (Ag2), - a third dielectric module (M3), - a third silver layer (Ag3), - a fourth dielectric module (M4), Including, the silver layers (Ag1, Ag2, Ag3) have relative geometric thicknesses of Ag2>Ag1>Ag3, and the silver layers (Ag1, Ag2, Ag3) of the solar shielding coating have relative geometric thicknesses of 1.0<Ag1 / Ag3 and 1.2<Ag2 / Ag3<2, said dielectric modules (M1, M2, M3, M4) consist of one or more dielectric layers based on silicon nitride, mixed silicon metal nitrides, aluminium nitride, tin oxide, manganese oxide, tungsten oxide, niobium oxide, bismuth oxide, zinc oxide or mixed tin-zinc oxide; The composite pane is for separating an interior from an exterior environment in a window opening, the inner pane referring to the pane of the composite pane facing the interior and the outer pane referring to the pane facing the exterior environment; Composite pane (100).

2. 2. The composite pane (100) of claim 1, wherein the dielectric modules (M1, M2, M3, M4) have relative optical layer thicknesses of M2 / M1 > 1.9, M2 / M3 > 0.8, and M2 / M4 > 2.

3. 3. The composite pane (100) of claim 1 or 2, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3), and / or the fourth dielectric module (M4) have at least one dielectric layer based on silicon nitride.

4. The composite pane (100) according to any one of claims 1 to 3, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3) and / or the fourth dielectric module (M4) comprise at least one first dielectric layer based on silicon nitride and at least one second dielectric layer based on zinc oxide.

5. 5. A composite pane according to any one of claims 1 to 4, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3) and / or the fourth dielectric module (M4) comprise at least one first dielectric layer based on silicon nitride, at least one second dielectric layer based on zinc oxide and at least one third dielectric layer based on mixed tin-zinc oxide.

6. 6. Composite pane according to any one of the preceding claims, wherein the solar shielding coating (4) comprises at least one metal blocking layer (B1, B2, B3) above and / or below the silver layer (Ag1, Ag2, Ag3), respectively, having a geometric thickness of less than 1 nm.

7. 7. The composite pane according to any one of claims 1 to 6, wherein the first silver layer (Ag1), the second silver layer (Ag2) and the third silver layer (Ag3) each have a geometric thickness of 5 nm to 25 nm.

8. said first silver layer (Ag1) having a geometric thickness of 7 nm to 14 nm; said second silver layer (Ag2) having a geometric thickness of 7 nm to 16 nm; the third silver layer (Ag3) has a geometric thickness of 6 nm to 13 nm; 8. The composite pane of claim 7.

9. 9. A composite pane according to any one of claims 1 to 8, wherein the first dielectric module (M1), the second dielectric module (M2), the third dielectric module (M3) and the fourth dielectric module (M4) each have a geometric thickness of 10 nm to 100 nm, preferably 20 nm to 90 nm, particularly preferably 70 nm to 85 nm.

10. A composite pane according to any one of the preceding claims, wherein the solar shielding coating (4) is applied to the outer surface (III) of the inner pane (1).

11. A composite pane according to any one of the preceding claims, wherein the solar shielding coating (4) comprises at least two busbars via which the solar shielding coating (4) can be connected to a voltage source.

12. A composite pane according to any one of the preceding claims, wherein a heating wire is present between the outer surface (III) of the inner pane (2) and the inner surface (II) of the outer pane (I).

13. A composite pane according to any one of the preceding claims, wherein the solar shielding coating (4) comprises exactly three silver layers (Ag1, Ag2, Ag3).

14. at least, (a) applying a solar shading coating (4) to the inner surface (II) of the outer pane (1) or to the outer surface (III) of the inner pane (2) or incorporating a solar shading coating (4) in a thermoplastic intermediate layer (3), (b) producing a stack of layers comprising at least said outer pane (1), said thermoplastic intermediate layer (3) and said inner pane (2), in that order; and (c) bonding a stack of layers including at least the outer pane (1), the thermoplastic intermediate layer (3), and the inner pane (2) to form a composite pane (100), A method for manufacturing a composite pane (100) according to any one of claims 1 to 13.

15. Use of a composite pane (100) according to any one of claims 1 to 13 in a motor vehicle, preferably as a windscreen, rear window, side window and / or roof panel, particularly preferably as a motor vehicle windscreen.

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